diff --git a/core/modules/commander.js b/core/modules/commander.js
index fe796fd7c5..2039bc15b1 100644
--- a/core/modules/commander.js
+++ b/core/modules/commander.js
@@ -95,8 +95,8 @@ Commander.prototype.executeNextCommand = function() {
 					this.streams.output.write("Executing command: " + commandName + " " + params.join(" ") + "\n");
 				}
 				// Parse named parameters if required
-				if(command.info.namedParameters) {
-					params = this.extractNamedParameters(params,command.info.namedParameters);
+				if(command.info.namedParameterMode) {
+					params = this.extractNamedParameters(params,command.info.mandatoryParameters,command.info.optionalParameters);
 					if(typeof params === "string") {
 						return this.callback(params);
 					}
@@ -130,23 +130,35 @@ Commander.prototype.executeNextCommand = function() {
 };
 
 /*
-Given an array of parameter strings `params` in name:value format, and an array of mandatory parameter names in `mandatoryParameters`, returns a hashmap of values or a string if error
+Given an array of parameter strings `params` in name:value format, and an array of mandatory parameter names in `mandatoryParameters`, and an array of optional parameters in
+`optionalParameter`, returns a hashmap of values or a string if error
 */
-Commander.prototype.extractNamedParameters = function(params,mandatoryParameters) {
+Commander.prototype.extractNamedParameters = function(params,mandatoryParameters,optionalParameters) {
+	mandatoryParameters = mandatoryParameters || [];
+	optionalParameters = optionalParameters || [];
 	var errors = [],
 		paramsByName = Object.create(null);
+	// Extract the parameters
 	$tw.utils.each(params,function(param) {
-		var index = param.indexOf(":");
+		var index = param.indexOf("=");
 		if(index < 1) {
 			errors.push("malformed named parameter: '" + param + "'");
 		}
 		paramsByName[param.slice(0,index)] = param.slice(index+1);
 	});
+	// Check the mandatory parameters are present
 	$tw.utils.each(mandatoryParameters,function(mandatoryParameter) {
 		if(!$tw.utils.hop(paramsByName,mandatoryParameter)) {
 			errors.push("missing mandatory parameter: '" + mandatoryParameter + "'");
 		}
 	});
+	// Check there no parameters that are not mandatory or optional
+	$tw.utils.each(paramsByName,function(value,name) {
+		if(mandatoryParameters.indexOf(name) === -1 && optionalParameters.indexOf(name) === -1) {
+			errors.push("unknown parameter: '" + name + "'");			
+		}
+	});
+	// Return any errors
 	if(errors.length > 0) {
 		return errors.join(" and\n");
 	} else {
diff --git a/core/modules/commands/listen.js b/core/modules/commands/listen.js
index 3cb04f6810..4602a66b72 100644
--- a/core/modules/commands/listen.js
+++ b/core/modules/commands/listen.js
@@ -17,7 +17,9 @@ var Server = require("$:/core/modules/server.js").Server;
 exports.info = {
 	name: "listen",
 	synchronous: true,
-	namedParameters: [] // Use named parameters, but none of them are mandatory
+	namedParameterMode: true,
+	mandatoryParameters: [],
+	optionalParameters: ["port","host","rootTiddler","renderType","serveType","username","password","pathprefix","debugLevel"]
 };
 
 var Command = function(params,commander,callback) {
@@ -25,7 +27,6 @@ var Command = function(params,commander,callback) {
 	this.params = params;
 	this.commander = commander;
 	this.callback = callback;
-	this.knownParameters = ["port","host","rootTiddler","renderType","serveType","username","password","pathprefix","debugLevel"];
 };
 
 Command.prototype.execute = function() {
@@ -35,7 +36,7 @@ Command.prototype.execute = function() {
 	}
 	// Set up server
 	var variables = Object.create(null);
-	$tw.utils.each(this.knownParameters,function(name) {
+	$tw.utils.each(exports.info.optionalParameters,function(name) {
 		if($tw.utils.hop(self.params,name)) {
 			variables[name] = self.params[name];
 		}